Love Mikes posts.Interestingly it reminds of a statement I heard ten years apart. Once from an professor at Colombia school of engineering and again from a professor of neurology at Harvard.

To be truly wise it is more important to know what you don't know then the details of what you know. You can always research the later but will always fail in your endeavors if you don't accept the former.

Good thing my wife knows my on/off switch but too bad she also knows just how to push my buttons.

Getting back to the O.P. Down at the yard there's a ~60' steel bulbous bow trawler. We've had a lot of wind recently and given the size of the thing and the windage she went bump into something hard. ( don't know the details). The cut water and port side of the bow were struck when she was leaving to go south. There were three significant indents. What surprised me was when talking with yard hands was:
Dented areas could not be hammered out or forced out with hydraulics. Any indent stretches the metal so original shape cannot be restored. Just like with a car skin.
Dented area should be presumed weak and should ideally be cut out.
even if not struck on frames- frames and symmetry of the hull need to be examined closely. Repair may need to involve area much larger than area of apparent damage.
Area to be refinished will also encompass area much larger than apparent damage.
Mounts and welds quite some distance from point of impact also need to be examined and may have failed.

It's true the hull skin remained intact but the repair bill looks like it will be quite significant. Surprising so given the external damage did not seem so bad to my un educated eye.

This boat was fully framed. I can see how after repair she'll be "as good as new". I can't see in a similar circumstance how one could restore a frameless hull to it's original conformation if the dented portion of the hull was in a portion that was bent as part of the origami method?

Brent has made much of the strength and ease of building in steel. I have some limited knowledge of repairs in solid glass, cored glass/synethics, and cold molded wood. I thought metal repair was much, much easier.I thought that was one of the major advantages of metal boats. It was an eye opener to hear of the potential complexities of metal repair. Particularly if one wants to restore to original beauty and hull conformation. I think I gained understanding why with commercial boats it's not uncommon for dents to just be recoated and left alone.

Sounds like your yard hands really know how to talk their way into a lot of extra work and wages. Kinda like the sand blaster who will blast to white metal perfectly good paint, with nothing wrong with it, as soon as your back is turned. He is paid by the hour, the more hours the more pay.
My reference to toggle switch vs rheostat, was an interview with a neurologist on AM radio KGO San Francisco. He was talking about religious and political fanatics having the disorder. It was a reference to Mike's suggestion that a curve adds nothing to strength, until it reaches a certain point then and only then does it become suddenly stronger. The added strength starts as soon as the metal starts to curve, increasing gradually the more curve you put in. He has stated that Lloyds makes no allowance for this, and ABYC only 15%. The difference between a square pressure bottle and a round one is a whole lot more than 15%, and undeniably more than the Zero Lloyds gives. His posts contain many "either or, black or white " toggle switch type assertions.

Brent, I would never heckle guys like Ignaz Semmelweis, Eratosthenes (not Columbus - you're confusing him with Magellan - but even that's not correct in your example), Gutenberg (not Guttenburg), Franklin, or even Dr. Roger Bacon. Those guys were all enlightened geniuses.

I only heckle luddite morons who continually claim to be enlightened geniuses.

Had you been alive in their time, you would have heckled them mercilessly, and declared them all luddite morons. You are definitely of the groupthink , whatever is in style to think at the moment, type of advocate. Only the passage of time, and history since then, gives you the benefit of hindsight, foresight not being anywhere in your makeup.

Had you been alive in their time, you would have heckled them mercilessly, and declared them all luddite morons. You are definitely of the groupthink , whatever is in style to think at the moment, type of advocate. Only the passage of time, and history since then, gives you the benefit of hindsight, foresight not being anywhere in your makeup.

I don't wear makeup.

As I said, I love innovation and new technologies - and admire those who enable them. Luddites, on the other hand, are those who fight against these things. You are absolutely one of these. And you absolutely are not anywhere near those geniuses you list. They were right -as time has proven. You are mostly wrong - also as time has proven. It's really that simple.

As I said, I love innovation and new technologies - and admire those who enable them. Luddites, on the other hand, are those who fight against these things. You are absolutely one of these. And you absolutely are not anywhere near those geniuses you list. They were right -as time has proven. You are mostly wrong - also as time has proven. It's really that simple.

But keep dreaming dude...if it helps.

Origami metal boatbuilding is anew technology, which you vehemently oppose, while studiously avoid trying to comprehend. You have vehemently opposed any innovations I have suggested without ever coming up with a single one of your own.
Makes you a luddite, by your own definition.

I typed up a long reply to Mike Johns questions, which someone either signed me off the site, or deleted before I could post it.

Thanks a lot!
I will repost it in a few days ,one paragraph at a time , with lots of use of the edit button, so I cant lose to much at once.
Meanwhile, a nice Northwesterly is forecast to give me a great sail tomorrow.

Brent although I'm not a Trawler kind of guy I can appreciate the beauty of this particular vessel. I had hoped you would address the question asked not clumsily try to make a blind attack. The yard folks know it wasn't my boat. They also know I'm not writing the checks. They finally know the owner wants his/ hers boat returned to its pre damaged state. I would appreciate input on how you would do this with one of your designs. Instead of throwing stones, if you have the stones please answer.

Brent in the past I wanted to be an ee not civil or mech e. But I seem to recall complex curved materials resist deformation to a greater extent than simple curves. I also seem to recall even with simple curved trusses curvature does not produce a linear response as regards deformation. In simple terms a little curve gives a little improvement but a little more gives much,much more. Perhaps mike would know if this is correct and the equation. I also recall that thickening the skin is not nearly as effective as even modest framing.

Brent in the past I wanted to be an ee not civil or mech e. But I seem to recall complex curved materials resist deformation to a greater extent than simple curves. I also seem to recall even with simple curved trusses curvature does not produce a linear response as regards deformation. In simple terms a little curve gives a little improvement but a little more gives much,much more. Perhaps mike would know if this is correct and the equation. I also recall that thickening the skin is not nearly as effective as even modest framing.

Correct. This is basic engineering, solid mechanics. Generally, shape is much more important and effective than material properties. Shape usually goes as ~r**2 (as in Steiners theorem) or ~r**4 whereas typical material as thickness of course is linear in r (r being a typical distance).

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register. Please enter your desired user name, your email address and other required details in the form below.Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:

Password

Please enter a password for your user account. Note that passwords are case-sensitive.

Password:

Confirm Password:

Email Address

Please enter a valid email address for yourself.

Email Address:

Log-in

User Name

Remember Me?

Password

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.